What is the least number of colors needed to shade the tessellation shown, such that no two tiles sharing a side are the same color?

[asy]
draw((-8,-2)--(8,-2));
draw((-8,2)--(8,2));
draw((-8,6)--(8,6));
draw((-8,10)--(8,10));
draw((-8,14)--(8,14));
path a=(-8,14)--(-6.5,12)--(-10,8)--(-6.5,4)--(-10,0)--(-8,-2);
draw(a);
draw(shift((4,0))*a);
draw(shift((8,0))*a);
draw(shift((12,0))*a);
draw(shift((16,0))*a);
[/asy]
Explanation: Clearly one color isn't enough; $\boxed{2}$ colors will work because the tessellation shown is topologically identical to a chessboard (that is, imagine straightening out the diagonal lines to form an array of squares. This process doesn't change which tiles share a side.).